Residency · Residency · Cardiology

Percutaneous Coronary Intervention: Techniques and Outcomes

Vascular Access

Radial vs. Femoral

Radial artery access has been established as the preferred approach for percutaneous coronary intervention, carrying a Class I recommendation in the 2021 ACC/AHA guidelines. The MATRIX and RIVAL trials demonstrated that radial access reduces bleeding complications, vascular complications, and mortality in patients presenting with acute coronary syndromes compared to the femoral approach. Right radial access is the most commonly used default owing to familiar anatomy and operator comfort, while left radial access offers better catheter alignment with the descending aorta and may facilitate left coronary engagement. Distal radial access through the anatomic snuffbox has gained increasing popularity as an alternative left radial site.

Femoral access remains necessary for procedures requiring large-bore access, such as mechanical circulatory support device insertion and transcatheter aortic valve replacement, as well as for certain complex interventions. Standard femoral procedures utilize 6 to 8 French sheaths, and a variety of vascular closure devices including Angio-Seal, Perclose, and MANTA for large-bore access are available to achieve hemostasis. When using radial access, prevention of radial artery spasm is achieved through an intra-arterial cocktail of verapamil at 2.5 to 5 mg combined with nitroglycerin at 200 micrograms or nicardipine. Prevention of radial artery occlusion following the procedure requires a patent hemostasis protocol, which involves confirming ulnar backbleed and applying a hemostasis band with minimal occlusive pressure.

Coronary Stents

Bare Metal Stents (BMS)

Bare metal stents were historically important in the development of percutaneous coronary intervention but have been largely replaced by drug-eluting stents in contemporary practice. Their use is now limited to specific scenarios including patients who require very short dual antiplatelet therapy because of urgent surgery within 30 days, patients at high bleeding risk who cannot tolerate any duration of dual antiplatelet therapy, and cases involving very large vessels exceeding 5 mm in diameter. The major limitation of bare metal stents is their high rate of in-stent restenosis, occurring in 20 to 30% of cases at 1 year, driven primarily by neointimal hyperplasia.

Drug-Eluting Stents (DES)

Current-generation drug-eluting stents, including everolimus-eluting platforms such as Xience and Synergy and zotarolimus-eluting platforms such as Resolute Onyx, incorporate biodegradable polymer or polymer-free designs that have dramatically reduced in-stent restenosis rates to 5 to 8%, a marked improvement over the 20 to 30% rates seen with bare metal stents. Very late stent thrombosis occurring beyond 1 year has become rare with current-generation devices, estimated at approximately 0.2 to 0.5% per year, largely mitigated by improved polymer biocompatibility and thinner stent struts. Appropriate stent sizing targets a 1:1 ratio with the reference vessel diameter, and intravascular ultrasound or optical coherence tomography-guided sizing is associated with better outcomes than angiographic assessment alone. Slight oversizing with drug-eluting stents is acceptable to optimize expansion.

Bioresorbable Vascular Scaffolds (BRS)

The concept of bioresorbable vascular scaffolds was developed to provide temporary scaffolding that would completely resorb over time, restoring native vessel biology. The Absorb bioresorbable scaffold from Abbott was initially promising but ultimately demonstrated higher rates of scaffold thrombosis and target lesion failure compared to drug-eluting stents in the ABSORB III trial, leading to its withdrawal from the market. Next-generation bioresorbable scaffolds with thinner struts and improved materials, including magnesium-based designs, remain under investigation but are not currently recommended for routine clinical use.

PCI Techniques

Lesion Preparation

Adequate lesion preparation is fundamental to achieving optimal stent deployment outcomes. Standard predilation uses semi-compliant balloon angioplasty with a balloon sized 0.5 mm below the reference vessel diameter. Non-compliant balloons, capable of achieving inflation pressures up to 20 to 30 atmospheres, are used for stent post-dilation to optimize expansion. Scoring and cutting balloons concentrate force focally and are particularly useful for resistant lesions, in-stent restenosis, and fibrocalcific disease.

For severely calcified lesions, several atherectomy techniques are available. Rotational atherectomy using the Rotablator employs a diamond-tipped burr rotating at 140,000 to 180,000 revolutions per minute to ablate calcified plaque, with a burr-to-artery ratio of 0.5 to 0.7 and a slow pecking motion. Complications include slow flow or no-reflow, perforation, and dissection. Orbital atherectomy with the Diamondback 360 system uses an eccentric diamond-coated crown that orbits at variable speeds to create an elliptical lumen, offering particular advantages for eccentric calcification. Intravascular lithotripsy, using the Shockwave system, has emerged as an increasingly first-line approach for severe calcification. This balloon-based technology delivers sonic waves that fracture both superficial and deep calcium without requiring a guidewire exchange, and has demonstrated an excellent safety and efficacy profile in the DISRUPT CAD III trial. Excimer laser provides photoablative treatment and is useful for in-stent restenosis, underexpanded stents, thrombotic lesions, and saphenous vein graft interventions.

Complex PCI Scenarios

Left Main PCI

Percutaneous intervention for left main coronary artery disease remains one of the most debated areas in interventional cardiology. The EXCEL trial demonstrated that PCI was non-inferior to coronary artery bypass grafting at 3 years for left main disease with low-to-intermediate SYNTAX scores below 33, though the 5-year results showed more deaths with PCI, driven by cardiac death, with controversial endpoint adjudication. The NOBLE trial found PCI to be inferior to bypass grafting for left main disease at 5 years. Current guidelines favor bypass grafting for most left main disease, with PCI considered reasonable when the SYNTAX score is 32 or below, anatomy is favorable for percutaneous intervention such as ostial or body disease with favorable bifurcation anatomy, or when surgical risk is elevated. Technical considerations for left main PCI include a preference for provisional single-stent strategy for bifurcation lesions, DK-CRUSH or culotte techniques when two-stent deployment is necessary, and mandatory use of intravascular ultrasound or optical coherence tomography guidance.

Bifurcation PCI

The management of coronary bifurcation lesions follows established algorithmic approaches. Provisional stenting, in which the main branch is stented and the side branch is treated only if compromised, is the preferred strategy based on the NORDIC I and EBC TWO trials. When a two-stent approach is required, typically for true bifurcation lesions with a diseased side branch of 2.5 mm or greater, several techniques are available including DK-CRUSH (double kissing crush), culotte, T-stenting, and TAP (T-stenting and small protrusion). The DKCRUSH-V trial demonstrated that the DK-CRUSH technique is superior to provisional stenting for true bifurcation lesions with large diseased side branches, providing improved freedom from target lesion revascularization. Final kissing balloon inflation is mandatory in all two-stent techniques to optimize stent expansion and neo-carina geometry.

Chronic Total Occlusion (CTO) PCI

Chronic total occlusions, defined as 100% coronary occlusions with TIMI 0 flow and an estimated duration of 3 months or more, are found in 15 to 25% of patients undergoing coronary angiography and have historically been managed medically. The EURO-CTO, DECISION-CTO, and REVASC trials have shown that CTO PCI improves angina and quality of life but has not demonstrated a mortality benefit, with DECISION-CTO showing no difference in major adverse cardiovascular events. Contemporary CTO PCI follows a hybrid algorithm that progresses from antegrade wire escalation to antegrade dissection-reentry to retrograde approaches, with strategy selection based on cap morphology, vessel course, and collateral quality.

Antegrade wire escalation begins with standard guidewires and progresses to CTO-dedicated wires such as Gaia and Conquest Pro, including polymer-jacketed tip wires, with microcatheter support from devices such as Corsair and Turnpike. Antegrade dissection-reentry employs the CrossBoss catheter for blunt dissection through the CTO body combined with the Stingray balloon, a flat balloon with directed puncture capability to reenter the true lumen. The retrograde approach involves crossing through a collateral channel, either septal or epicardial, to cross the CTO from the distal end, with reverse CART (controlled antegrade and retrograde subintimal tracking) as a key technique. Success rates at experienced centers reach 85 to 90%, though perforation rates of 3 to 5% and tamponade rates of approximately 1% must be considered, along with higher contrast use and radiation exposure compared to standard PCI.

Saphenous Vein Graft (SVG) PCI

Percutaneous intervention on degenerated saphenous vein grafts presents unique challenges due to the friable, thrombotic nature of the graft material and the high risk of distal embolization and no-reflow phenomenon. Embolic protection devices, either distal filters such as FilterWire and SpiderFX or proximal occlusion devices such as Proxis, are essential for reducing periprocedural myocardial infarction. The SAFER trial demonstrated a 42% reduction in major adverse cardiovascular events with the use of distal protection. Direct stenting without predilation is preferred to reduce plaque shift and embolization. Covered stents have not demonstrated benefit over drug-eluting stents for saphenous vein graft lesions. Glycoprotein IIb/IIIa inhibitors should be avoided in saphenous vein graft PCI as they provide no benefit and increase bleeding risk.

<image> A step-by-step illustration of intravascular lithotripsy (IVL) for severely calcified coronary lesions. Four sequential panels showing cross-sectional views of a coronary artery. Panel 1 (Pre-treatment): severely calcified lesion with concentric calcium (shown in white/yellow) surrounding the lumen; the lumen is severely narrowed. IVUS image inset showing 360-degree calcium arc with acoustic shadowing. Panel 2 (IVL balloon inflation): the Shockwave IVL balloon is inflated at low pressure (4 atm) within the calcified lesion; sonic pulse emitters on the balloon are shown generating concentric shockwaves (depicted as radiating circles in blue). Panel 3 (Calcium fracture): the calcium ring shows multiple fracture lines (cracks in the calcium depicted as dark lines through the white calcium deposits); the lumen begins to open. Panel 4 (Post-stenting): a drug-eluting stent is fully expanded in the treated segment with excellent apposition; the fractured calcium allows the stent to achieve full expansion. IVUS image inset showing well-expanded stent with fractured calcium and no malapposition. Each panel labeled with the step name. Include a small inset showing the IVL balloon with the emitter positions labeled. </image>

Intravascular Imaging-Guided PCI

IVUS

Intravascular ultrasound utilizes grayscale ultrasound at frequencies of 20 to 60 MHz, providing tissue penetration of 4 to 8 mm with an axial resolution of 100 to 150 micrometers. This modality assesses lumen area, plaque burden, vessel remodeling, stent expansion, edge dissection, and stent malapposition. Optimal stent expansion is defined by a minimum stent area of 80% or greater of the reference vessel area, or 5.5 mm squared or greater in large vessels. The ADAPT-DES study demonstrated that intravascular ultrasound-guided PCI reduced stent thrombosis by 48% and major adverse cardiovascular events at 1 year compared to angiography-guided procedures. The ULTIMATE trial further confirmed that intravascular ultrasound-guided drug-eluting stent implantation reduced target vessel failure by 48% at 3 years.

OCT

Optical coherence tomography employs near-infrared light interferometry to achieve a resolution of 10 to 20 micrometers, approximately 10 times better than intravascular ultrasound, though with a more limited tissue penetration of 1 to 3 mm. This superior resolution makes optical coherence tomography particularly advantageous for identifying thin-cap fibroatheroma with a cap thickness below 65 micrometers, detecting stent strut malapposition, evaluating stent edge dissection, identifying thrombus, and differentiating plaque erosion from plaque rupture in acute coronary syndromes. The ILUMIEN IV trial demonstrated that optical coherence tomography-guided PCI was non-inferior to intravascular ultrasound-guided procedures for target vessel failure and achieved superior minimum stent area expansion. The OCTOBER trial showed that optical coherence tomography-guided PCI reduced major adverse cardiovascular events in complex bifurcation PCI compared to angiography-guided procedures. The principal limitations of optical coherence tomography include the requirement for blood clearance through contrast injection, limited penetration depth, and inability to image through thick calcification.

When to Use Intravascular Imaging

Intravascular imaging is strongly recommended in several clinical scenarios: left main PCI, in-stent restenosis evaluation, stent thrombosis evaluation, assessment of ambiguous lesion severity, and chronic total occlusion PCI. It is considered reasonable for all complex PCI, bifurcation PCI, severely calcified lesions, and cases involving long stent lengths. The RENOVATE-COMPLEX PCI trial provided definitive evidence that imaging-guided PCI using either intravascular ultrasound or optical coherence tomography reduced target vessel failure by 37% compared to angiography-guided procedures in complex lesions.

Antithrombotic Therapy After PCI

DAPT Duration After Elective PCI

The standard duration of dual antiplatelet therapy following elective PCI consists of aspirin plus a P2Y12 inhibitor, with clopidogrel at 75 mg daily preferred for stable coronary artery disease, for 6 months, followed by aspirin monotherapy. Short-duration dual antiplatelet therapy of 1 to 3 months is considered reasonable in patients at high bleeding risk, supported by the MASTER DAPT, STOPDAPT-2, and SMART-CHOICE trials, which demonstrated acceptable ischemic outcomes with this approach. P2Y12 inhibitor monotherapy after short dual antiplatelet therapy has gained support from the TWILIGHT, TICO, and STOPDAPT-2 trials, which demonstrated that early aspirin cessation with continued ticagrelor or clopidogrel monotherapy reduces bleeding without increasing ischemic events. Extended dual antiplatelet therapy beyond 12 months should be considered for patients at high ischemic risk, including those with prior stent thrombosis, complex PCI, or diabetes with multivessel disease. The DAPT study showed that extended therapy reduced stent thrombosis and myocardial infarction but increased bleeding risk.

DAPT Duration After ACS

Following acute coronary syndromes, the standard duration of dual antiplatelet therapy is 12 months using aspirin plus a potent P2Y12 inhibitor, with ticagrelor or prasugrel preferred over clopidogrel. De-escalation strategies, involving a switch from ticagrelor or prasugrel to clopidogrel at 1 to 3 months, are supported by the TOPIC and TROPICAL-ACS trials as guided de-escalation approaches. Short-duration dual antiplatelet therapy in the acute coronary syndrome population has limited data and should be considered only in patients at very high bleeding risk.

Triple Therapy (Anticoagulation + DAPT)

The management of patients requiring oral anticoagulation for conditions such as atrial fibrillation, mechanical valve prostheses, or venous thromboembolism who also undergo PCI represents a challenging clinical scenario. A consistent body of evidence from the WOEST, PIONEER AF-PCI, RE-DUAL PCI, AUGUSTUS, and ENTRUST-AF PCI trials has shown that dual therapy combining oral anticoagulation with a P2Y12 inhibitor reduces bleeding compared to triple therapy without increasing ischemic events. The current approach employs triple therapy with oral anticoagulation, aspirin, and clopidogrel for the shortest possible duration of 1 week to 1 month, followed by dual therapy with oral anticoagulation and clopidogrel for up to 6 to 12 months, and then oral anticoagulation alone. Direct oral anticoagulants are preferred over warfarin, with lower doses utilized as established in the relevant trials, including rivaroxaban 15 mg, dabigatran 110 mg, and apixaban 5 mg as used in AUGUSTUS.

Complications of PCI

Periprocedural

Coronary dissection is classified according to the type A through F system, with flow-limiting dissections requiring stenting while small non-flow-limiting dissections may be observed. Coronary perforation follows the Ellis classification: Type I consists of an extraluminal crater, Type II involves pericardial or myocardial staining, and Type III presents as jet perforation with cavity streaming. Type III perforations require covered stent placement or coil embolization, with pericardiocentesis performed if tamponade develops. No-reflow occurs from distal microvascular obstruction caused by embolic debris, platelet aggregation, and vasospasm, and is treated with intracoronary adenosine at 100 to 200 micrograms, nitroprusside at 100 to 200 micrograms, or epinephrine at 50 to 200 micrograms. Abciximab should be avoided in saphenous vein graft procedures. Contrast-induced nephropathy typically manifests as a serum creatinine rise at 48 to 72 hours, peaking at 3 to 5 days. Prevention strategies include hydration at 1 to 1.5 mL/kg/hour for 12 hours before and after the procedure, minimizing contrast volume to less than 3.7 times the glomerular filtration rate in milliliters, using iso-osmolar contrast such as iodixanol, and holding nephrotoxic medications.

Stent-Related

In-stent restenosis results from neointimal hyperplasia in the case of drug-eluting stents or neoatherosclerosis in late presentations, and typically presents with recurrent angina. Treatment options include drug-coated balloon therapy, implantation of a drug-eluting stent within the prior stent, or coronary artery bypass grafting for recurrent diffuse in-stent restenosis. Stent thrombosis is classified by timing as acute (within 24 hours), subacute (1 to 30 days), late (1 to 12 months), or very late (beyond 12 months), and presents as acute myocardial infarction or sudden cardiac death. Common causes include dual antiplatelet therapy discontinuation, stent malapposition, stent underexpansion, and edge dissection, and the condition carries a mortality of 10 to 25%. Stent fracture is rare but occurs more commonly with overlapping stents, at hinge-point motion locations such as the right coronary artery, and in heavily calcified lesions.

Key Clinical Pearls

• Radial access should be the default approach for all PCI -- the mortality benefit in ACS is well-established, and vascular complications are significantly lower than femoral
• Intravascular imaging (IVUS or OCT) should be used for all complex PCI -- RENOVATE-COMPLEX showed a 37% reduction in target vessel failure; imaging is especially critical for left main, bifurcation, CTO, and calcified lesions
• Intravascular lithotripsy has transformed the treatment of severely calcified lesions -- it fractures both superficial and deep calcium without the wire exchange requirements of rotational atherectomy, and has an excellent safety profile
• For patients on OAC requiring PCI, triple therapy should be minimized to the shortest possible duration (1 week to 1 month) -- AUGUSTUS established that dual therapy (DOAC + P2Y12 inhibitor, dropping aspirin early) is the safest effective strategy
• Stent thrombosis is most commonly caused by premature DAPT discontinuation or stent underexpansion -- always verify adequate expansion with high-pressure post-dilation and intravascular imaging
• CTO PCI improves symptoms and quality of life but has not demonstrated mortality benefit -- patient selection should focus on symptomatic patients with viable myocardium in the CTO territory and objective ischemia

References

• Lawton JS, et al. 2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization. Circulation. 2022;145:e4-e17.
• Mehran R, et al. Standardized Bleeding Definitions for Cardiovascular Clinical Trials: BARC Consensus. Circulation. 2011;123:2736-2747.
• Lopes RD, et al. Antithrombotic Therapy After Acute Coronary Syndrome or PCI in Atrial Fibrillation (AUGUSTUS). NEJM. 2019;380:1509-1524.
• Hill JM, et al. Intravascular Lithotripsy for Treatment of Severely Calcified Coronary Artery Disease (DISRUPT CAD III). JACC. 2020;76:2635-2646.
• Lee JM, et al. Intravascular Imaging-Guided or Angiography-Guided Complex PCI (RENOVATE-COMPLEX PCI). NEJM. 2023;388:1668-1679.

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